Volume 88, Issue 6
November 1979, pages 413-486
pp 413-422 November 1979
In the taxonomically unsatisfactory grouping of the Nymphaeaceaesensu lato, an attempt has been made to analyse the role of sclereids in different taxa to understand the taxonomic range of this character. The presence or absence of sclereids tends to support familial segregations as suggested by recent workers. Further, it is concluded that their occurrence is not a part of character-syndrome of any particular ecological niche.
pp 423-433 November 1979
Three latosols that fix applied soluble phosphate most avidly were dressed with labelled single superphosphate and potato plants were grown on them, with or without artificial inoculation with spores of endomycorrhizae. Mycorrhizal plants were found to accumulate more phosphate, especially from the ferruginous Ootacamund soil, which has the strongest affinity for phosphate. Fractional chemical and radio-chemical analyses of the soils, before and after the plant culture, together with other available evidences, point to the conclusion that the endophyte can attack and mobilise such fractions of phosphate in latosols that are least available to potato plants. Further confirmation for this conclusion came from a sand culture experiment, in which mycorrhizal and non-mycorrhizal potato plants were either dressed with labelled AIPO4 and FePO4, or fed with saturated solutions thereof; it was found that, in the former case, plant uptake was much larger although the specific activities remained unchanged.
pp 435-443 November 1979
The morphology and embryology ofDaucus muricatus (L.) L. is studied. In the light of embryological characteristics, the systematic position ofDaucus in the Umbelliferae is discussed.
pp 445-450 November 1979
The apparently healthy area around the yellow halo of the spots formed by infection of turmeric leaves byColletotrichum capsici as well as by the treatment of toxin secreted by the pathogen was found to behave differently in certain biochemical properties from healthy area. This area had a hyper rate of respiration, a lower photosynthetic rate and a reduction in major photosynthetic pigments. This biochemically different area can be considered as a prehalo.
pp 451-453 November 1979
The presence of an additional lower palisade in varieties ofGossypium arboreum andG. herbaceum was confirmed. Except vars. Sujata and PSH, in other varieties ofG. barbadense spongy tissue was thicker than palisade. InG. hirsutum, varieties grown under irrigated and assured rainfall conditions had thicker upper epidermis and the differences in thickness of palisade and spongy tissues per genotype were less than those found in varieties growing under limited supply of moisture. It appeared that greater difference of palisademinus spongy parenchyma inG. hirsutum cottons is a better indicator of drought tolerance than palisade thickness alone or total thickness of the leaf.
pp 455-461 November 1979
The embryology ofF1 progeny of reciprocal crosses between R473 and 302 has been investigated. The anther wall development follows the monocotyledonous type. Successive cytokinesis in the microspore mother cells results in the formation of isobilateral pollen tetrads. Pollen grains are 3-celled at the shedding stage. Although 90% of pollen are fertile, the germination is only about 70%. Abortive pollen grains are noticed in some anthers. The ovule is anatropous, bitegmic and pseudocrassinucellar. Archesporium or megaspore mother cell, if formed, degenerates. The embryo sac developed aposporously from a nucellar cell, is always 8-nucleate with a secondary increase in the antipodal cells. Fertilisation does not take place. The autonomous development of embryo and endosperm occurs under the stimulus of pollination. Like the two parents theF1 progeny exhibit apomixis of the nature of somatic apospory associated with self-incompatibility.
pp 463-472 November 1979
Cells of the resting vascular cambium ofFagus sylvatica contain vesiculate smooth endoplasmic reticulum, free ribosomes, oil droplets, protein bodies and few or no vacuoles. Active cambial cells and young differentiating xylem elements are highly vacuolate and contain rough cisternal ER and polyribosomes. The Golgi apparatus is active in the production of vesicles and particles of about 25 nm diameter are found just outside the plasmalemma of differentiating xylem cells. The possibility that vacuoles are formed by the progressive dissolution of stored proteins during the onset of cambial activity, and that protein bodies are formed by deposition of storage products in vacuoles, is confirmed.
pp 473-478 November 1979
Seed structure and seedling anatomy ofCajanus cajan are investigated. Seeds are non-endospermic. Initially ovules are anatropous but later they become campylotropous. The epidermis and the hypodermis of the seed coat consist of macrosclereids and osteosclereids respectively. Macrosclereids have fluted wall thickenings. The “tracheid island” has cells with lignified reticulate wall thickenings. Vascular interrelationship between the radicle, epicotyl and first pair of leaves have been described.
pp 479-486 November 1979
Preheating and heated teliospore extracts have been found to be stimulatory to germination of the teliospores of ten different smut fungi used in this study. The effect is mostly on the percentage of germination.
Maximum per cent of spore germination was observed at higher concentrations of glucose and sucrose solutions. The percentage of germination of spores of the species included was more in sucrose than in glucose. Most of the vitamins of B-complex groups stimulated the initiation of germ tube.
Many of the growth regulators tried, except 2,4-dichlorophenoxy acetic acid have a stimulatory effect on teliospore germination. Higher percentage of teliospore germination was noticed in the case of gibberellic acid, followed by indole 3-acetic acid, beta-indole butyric acid and alphanaphthalene acetic acid.
Ethylenediamine tetraacetic acid, furfural, fumaric acid, oxalic acid and citric acid were also stimulatory, in that order.